Switching device



Jan. 19, 1943. A. A) JOHNSON SWITCHING DEVICE Filed Aug. l, 1940 bill/1A W" 'lull/lill! INVENTOR Patented Jan. 19, 1943 UNITED STATES PATENT OFFICE SWITCHING DEVICE Arthur A. Johnson, Bridgeport, Conn., 'assigner to Casco Products Corporation, Bridgeport, Conn., a corporation of Connecticut Application August 1, 1940, Serial No.y 349,064;

9 Claims.

This invention relates to electric switches, and more particularly; to switches for controlling two circuits, either of which may be closed independently of the other.

An object of this invention is to provide, in a unitary structure, two separate switch mechanisms, one of which preferably also constitutes a rheostat, so that two separate circuits may be conveniently controlled from a single point and one of the circuits may be controlled so as to increase or decrease the current going .to the translating device.

The switch of the present invention is particularly adapted for use in connection with accessories employed on automobiles, and is designed to control a defroster circuit and a car heater circuit. The defroster circuit is usually either opened or closed, but, for controlling the car heater, it is desired to vary the speed of the fan motor, as well as to openand close the circuit thereof, and hence one of the controls of the switch of .the present invention also constitutes a rheostat.

According to the present invention in the form at present preferred, the switch has two manual controls, rotatably mounted, one within the other, one of the controls opening and closing the defroster circuit and the other control opening, closing and varying the heater control circuit. With the controls placed one within .the other, they may be independently operated, or they may be operated jointly by the operator by causing his fingers to grip both controls at .the A same time.

According to the present invention in itsr glzed, the condition resulting when the user, in-

tending to move the rheostat to the full-on position, leaves it in a position just short of full-on adjustment.

To avoid this diiliculty, the present invention provides a contact shield over the `resistance coil to prevent engagement of the contacter with the last few turns of the coil, and preferably this shield is connected to the binding post or other contact device which is connected directly to the battery so that the current will be fullon at all times when the contacter on the rheostat is moved to a position approximately at or adjacent to full-on position.

In the specific form of device herein disclosed, all direct engagement of the contact arm with the resistance coil is avoided by providing another contact shield connected to the other end of the resistance coil, the space between the two shields being bridged by an intermediate contact shield connected to the middle of the coil. With this construction, the rheostat has only four conditions of control-high, medium, low, and off. If a greater number of conditions are required, additional intermediate contact shields connected to said resistance wire at successive intervals may be employed.

In the preferred form of the invention, the contact arm and the contact points of the rheostat are suitably shaped so as to form detent elements whereby the contact arm and control therefor is positively held in the desired positions. Y

Another object of this invention is to provide a signal for visually indicating to the user when either lthe simple switch or the switch and rheostat, or both, are in circuit-closing position. For this purpose, an electric light bulb carried by the operating knob is caused to be energized when either the simple switch or the switch and rheostat have been moved away from the o position.

Other features and advantages will hereinafter appear.

In the accompanying drawing which shows one embodiment of the present invention, that at present preferred:

Figure 1 is a vertical axial cross-section of the switch device of the present invention.

Fig. 2 is a rear elevation of said switch.

Fig. 3 is a cross section substantially along the line 3 3' in Fig. 1 in the direction of the arrows, showing the contact shields and contact points of the switch.

Fig. 4 is a cross-section substantially along the line 4-4' in Fig. 1 in the direction of the arrows showing the contactors and various ositions thereof.

Fig. 5 is a front elevation oi the switch shown in Fig. 1.

Fig. 6 is a detail of clamping means for securing the switch of Fig. 1 to an automobile dashboard.

Fig. 7 is a detail in cross-section of a terminal screw and contact point at the full-on end of the rheostat.

As shown in the accompanying drawing, the

electric switch device of the present invention is a unitary structure comprising two separate manually operated switches, one of which also constitutes a rheostat, adapted respectively to operate a defroster circuit and a heater circuit from the dashboard of an automobile.

According to the present invention in the form at present preferred, the switches are housed in a cup-shaped casing I carrying an externally threaded bushing II, a nut I2 clamping the wall of said casing to a. iiange IIa on the bushing. The bushing II, which constitutes the neck of the switch device, is inserted through an aperture in a mounting bracket I3 and in a face plate I4, and is secured thereto by means of a nut I5. The said mounting bracket is provided with a thumb screw I6 so that the switch may be conveniently clamped to the dashboard of an automobile.

Two controls are rotatably mounted in the bushing II, a car heater control I1 fitting into a defroster control I8, said controls' being independently or jointly operable.

The defroster control I8 comprises a metal sleeve I9 rotatably carried by the bushing II, having at its inner end a depending arm 29 within the casing I0 and at its outer end a metal ring 2| secured thereto by tabs l9a bent into conforming slots on the portion 2Ia of the ring 2|. A resilient contactor 22 comprising two arms, 22a and 22h, is secured to the arm 20 by rivets 23 and is insulated therefrom as shown.

The car heater control I1 comprises a metal sleeve 24, mounted within the sleeve I9 and of such diameter as to rotate freely therein. At its inner end, the sleeve 24 carries a Winged plate 25, preferably of some rigid insulating material, secured thereto by a plurality of tabs 24a, and at its outer end, said sleeve carries a. translucent knob 26. An enlarged portion 24h is provided as shown at the knob-receiving end of the sleeve 24 to coniine the latter within the sleeve I9 against axial displacement.

The knob 26 is slidably assembled to the portion 24h of the sleeve 24 by means of a sleeve 21 having a key dent 21a engaging a slot 28 on the enlarged sleeve portion 24b. The knob 23 is thereby secured to the sleeve 24 for rotation therewith, although it may be easily removed therefrom for replacement of an electric bulb 32, enclosed in the hollow interior thereof.

A contactor 29 comprising two resilient ngers 30 and 3| is secured to the winged plate by tabs In order to indicate to the user when either or both switches are in circuit-closing position, the switch device is provided with a signal means comprising an electric light bulb 32 carried by a socket sleeve 33, key-dented to the sleeve 24.

At the rear of the switch device, a circular base plate 34, preferably of molded plastic insulating material, is carried by the casing I0 and rigidly clamped to the casing between lugs 35 and 38 as shown. The battery, defroster, and heater terminals and the contacts associated therewith are mounted on the base plate 34 and are so positioned as to complete electric circuits to the translating devices when the controls are manipulated.

If it is desired to operate the defroster, the ring 2| is rotated in a clockwise direction to "on position as indicated by suitable indicia on the ring and face plate, as shown in Fig. 5, to bring the contactor 22 into engagement simultaneously, with three Contact `plates mounted on the base plate 34, comprising a battery contact plate 31,

centrally positioned on the base plate 34, a signal bulb contact plate 38, and a defroster contact plate 39, radially disposed with reference to the contact plate 31. As shown in the drawing, contact arm 22a of contactor 22 engages defroster contact plate 39 While contact arm 22h engages battery contact plate 31 and signal bulb contact plate 38. In this on position, two circuits are completed, one from the battery to the defroster through a battery terminal 40, contact plate 31, contactor 22, contact plate 39, and defroster terminal 4I, and the other from the battery to the signal bulb 32, through the contact plate 31, contactor 22, contact plate 38, and a contact arm 42 extending from the contact plate 38 into the neck of the switch to the bulb 32, which is grounded through the sleeves 33, 24 and I9, bushing II, and bracket I3 to the dashboard of the automobile as shown, causing the signal bulb 32 to be illuminated.

If it is desired to operate the car heater, the knob 26 is rotated in a clockwise direction to bring the fingers 30 and 3| of the contactor 29, simultaneously into engagement with the contact plate 31, contact plate 38 and a variable portion of a resistance coil 43, carried by the base plate 34 as will be explained hereinafter. When the knob is thus operated, two circuits are simultaneously completed, one from the battery to the car heater through battery terminal 40, contact plate 31, contact finger 30, contact finger 3|, a variable portion of the resistance coil 43, and car heater terminal 45, and the other from the battery to the signal bulb 32, through battery terminal 40, contact plate 31, contact finger 30, contact plate 38, and contact arm 42.

In prior switches of this type comprising a rheostat, the contactor for the resistance coil rides on the surface of the latter, and it sometimes happens that only a few coils thereof are accidentally left in the circuit, particularly near "full-on position, this resulting in overheating of these coils and rapid deterioration of the same.

According to the present invention, this dimculty is avoided by cutting a portion of the resistance coil into the circuit indirectly. The resistance coil 43 is mounted in an arcuate channel 43 in the rear surface of the base plate 34. The coil 43 is secured in said channel at three spaced positions by binding posts, 41, 48, and 49. These posts are headed to U-shaped metal clamps 53, circumferentially engaging the resistance coil.

Since the wall 46a of the channel 46 insulates the coil 43 from contactor 3|, direct contact between said coil and contactor is avoided. In order to provide a contact between one end of said coil and the said contactor for "full-on adjustment, an arcuate contact plate or shield 5| on the surface of base plate 34 opposite the coil, is connected to binding post 41 and to car heater terminal 45. Contactor 3| engages said shield at all times when it is moved to a position approachfull-on" adjustment, thus establishing a direct circuit from the battery to the car heater.

For the purpose of including the entire resistance coil 43 in the heater circuit, a similar arcuate contact plate 52 is connected by binding post 49 to the opposite end of said coil, contactor 3| engaging the latter plate when approaching the position for low adjustment.

An intermediate binding post 48 connected to the midpoint of the coil 43, disposed on the inner surface of the base plate 34 between the two arculimiting the angular movement of said contacts to mutually exclusive angles; a plurality of arcuately spaced contacts adapted to be engaged respectively by said contactors upon manual adjustment thereof, at least two of said contacts lying within the angular 'range of motion of one of said contactors; a series of arcuately disposed contacts concentric with the first sexies and adapted to be engaged and disengaged by said contactors simultaneously with the contacts of the first series; a contact concentric with said series of contacts adapted to be engaged by either contactor as long as the latter engages a contact of s'aid arcuate series, all of said contacts lying substantially in the same plane; and means for connecting the second series of contacts with said signal lamp, whereby either contactor establishes a circuit from the common contact to the signal lamp whenever a circuit is closed from the common contact to one of the first series of contacts.

4. In a combined switch and rheostat device, a pair of hollow members concentrically mounted one within Iche other for mutually independent rotation; a pair of grip members mounted on the outer ends of said'rotary members respectively and adapted to be grasped with one hand for independent or simultaneous manipulation thereof a signal lamp mounted within the inner member; a pair of radial contactors carried by the inner ends of said members respectively; stop means limiting the angular motion of said contactors to mutually exclusive angles; a resistor element; a plurality of contacts connected at spaced intervals of said resistor, arcuately disposed about the axis of said rotary members within the range of one of said contactors, and adapted to be selectively engaged and disengaged thereby; a contact on an arc of the same circle., within the range of the other contactor, and adapted to be engaged at will thereby; a contact ring concentric with the aforementioned contacts and engaged by said contactors whenever one of said contacts is engaged by either contactor; a common contact engaged by both contactors as long as they engage one of the arcuately spaced contacts, said contact ring and said contacts being disposed in substantially the same plane; and means for connecting the contact ring to the signal lamp, whereby a circuit is completed from the common contact to the signal lamp whenever any of the other contacts is engaged by either of said contactors to close one or both of a pair of independent circuits, adjustment of the contactor cooperating with the resistor-engaging contacts varying the resistance of one of said circuits.

5. In a combined switch and rheostat device, a pair of hollow members concentrically mounted one within the other for mutually independent rotation; a pair of group members mounted on the outer ends of said members adapted to be grasped by one hand for simultaneous or independentI manipulation thereof; a signal lamp mounted in the hollow of the inner member, its illumination being visible from the outer end of said rotary members; a base plate mounted adjacent the inner end of said rotary members; a resistor element arcuately mounted on said base plate, concentric with said rotary members; a radial contactor .insulatedly mounted on the inner end of one of said rotary members, forming a connection to said resistor at various points thereon and interrupting said connection upon adjusting the rotary member to which it is attached; a switch contact mounted on the base plate at the same distance from the axis of said rotary members as said resistor element but angularly spaced from the latter; a radial contactor, carried by-the other rotary member, engaging the latter contact at will upon manipulation of said member; stop means limiting arcuate motion ofsaid contactors to mutually exclusive angles; a central contact carried by the base plate and engaged by both of said contactors; a contact ring on the surface of said base plate engaged by either of said contactors when a connection is formed thereby with the arcuate resistor, or with the switch contact adjacent thereto; and a resilient finger connected to said ring engaging one of the terminals of the signal lamp filament, the first contactor varying the resistance of a circuit between said centrai contact and the terminal of the resistance element, the second contactor opening and closing an independent circuit from said central contact to the other contact upon disengagement or engagement therewith, and either contactor closing a separate circuit from the central contact to said lamp filament through the contact ring whenever one of the aforesaid circuits is completed.

6. In a switch and rhecstat device, a pair of hollow members concentrically mounted one within4 the other for mutually independent rotation; a pair of grip members mounted on the outer ends of said members and adapted to be simultaneously or independently grasped by one hand for manipulation thereof; a signal lamp mounted in the hollow of the inner rotary member, its illumination being visible from the outer ends of said members; a base plate of insulating material mounted adjacent the inner ends of said members having an arcuate recess concentric with said members in its rear surface; a coiled resistance element mounted in said recess; a terminal carried by the base plate and connected to one end of said resistance element; a plurality of arcuately spaced contacts extending through said base plate from the front surface into said recess and connected to said resistor element at spaced intervals; a radial contactor insulatedly mounted on the inner end of one of said rotary members adapted to engage said contacts selectively on the front of the base plate; a switch `contact extending through said base plate on the same circle as the arcuately spaced contacts, but angularly spaced therefrom, said con- Atact including a terminal on the rear surface of the base plate; a radial contactor carried by the other rotary member adapted to engage and disengage the latter contact upon manipulation thereof; stop means limiting arcuate motion of said contactors tov mutually exclusive angles; a central contact extending through said base plate and including a terminal on the outer surface thereofl said contact being permanently engaged by both of said contactors; a contact ring on the surface of said base plate engaged by either of said contactors when one of the arcuately spaced contacts or the switch contact is engaged thereby;. and a resilient finger connected to said ring and engaging one of the terminals of the lamp filament, the first contactor selectively varying the resistance'of a circuit between said central contact and the resistance element terminal by selective engagement with the arcuately spaced contacts and interrupting said circuit upon disengagement from said contacts, the second contactor opening and closing an independent cirasoaasa cuit fromvsaid central contact to said terminal bearing switch contact upon disengagement or engagement therewith, and either contactor closing a third circuit from said central contact to said lamp filament through the contact ring whenever one of the aforesaid circuits is completed.

7. A combined switch and rheostat device as defined in claim 6, comprising yieldable detent means for retaining the contactors in any of the contact-engaging positions and contact-disengazing positions, the clearance between said arcuately spaced contacts, connectedl to said resistor, being sufllciently small to be bridged by the contact cooperating therewith during movement from one contact to the next.

8. In a rheostat, a base plate of insulating material having an arcuate recess in the rear surface thereof; a coiled resistor disposed in said recess; a plurality of arcuately spaced contacts mounted on the front surface of said plate and extending therethrough and into said recess; a current-conducting clip, carried by the end of each contact extending through said plate, circumscribingsaid resistor, each clip electrically connecting a contact to a point on said resistor and mechanically retainingv said resistor in said recess; a terminal on the rear surface of said plate electrically connected to one end of said resistor; a contact centrally carried by said plate on the front surface thereof and concentrically disposed relative to said arcuately spaced contacts; a terminal on the rear surface of said plate electrically connected to said central contact; a contact member having contact means in permanent engagement with said central contact and other contact means selectively movable into engagement with the arcuately spaced-contacts to complete a circuit from the terminal of said central contact through a selected portion of said resistor to the terminal thereof and manually operable means for moving said contact member to selectively move the last-named contact means thereof into engagement with the arcuately spaced contacts.

9. In a rheostat, a base plate of insulating material having an arcuate recess in the rear surface thereof; a coiled resistor disposed in said recess; a plurality of arcuately spaced contacts mounted on the front surface of said plate and extending therethrough and into the said recess; a current-conducting clip, carried by the end of each contact extending through said plate, circumscribing said resistor. each clip electrically.

connecting a contact to a point on said resistor and mechanically retaining said resistor in said recess, the contacts at the opposite ends of said arc being electrically connected to opposite ends of said resistor; an elongate arcuate conductive strip electrically connected to each of said lastnamed contacts and positioned on the front surface of said plate in alignment with said arcuately spaced contacts; a terminal on the rear surface of said plate electrically connected to one end of said resistor; a contact centrally carried by said plate on the front surface thereof and concentrically disposed relative to said arcuately spaced contacts; a terminal on the rear surface of said plate electrically connected to said central contact; and a contact member having contact means in permanent engagement with said central contact and other contact means selectively movable into engagement with the arcuately spaced contacts and the strips carried by said contacts at opposite ends of the arc to complete a circuit from the terminal of said cen trai contact through a selected portion of said resistor to the terminal thereof; and means for moving said contact member to selectively move the last-named contact means thereof into engagement with the arcuately spaced contacts and the strips in alignment therewith.

ARTHUR A. JOHNSON. 

